As much as 10 percent of the Earth's avian species may have been lost.

Human colonization of the Pacific Islands likely caused the extinction of nearly 1,000 species of large-bodied, flightless birds known as passerine landbirds.

A study of fossils from 41 Pacific islands found that two-thirds of bird populations on these islands went extinct in the period between the first arrival of humans and European colonization, or roughly from 3,500 to 700 years ago. Overhunting by humans, exacerbated by forest clearance, was a major cause of prehistoric bird extinctions.

Extinction rates between islands varied greatly but were higher for smaller islands and those with lower rainfall, which were more extensively deforested. Larger islands experienced lower rates of extinction, partially because they would have supported larger bird populations, but also because their diverse topography would have included forests in less accessible areas, making deforestation and hunting difficult.

Species’ traits also influenced the probabilities of extinction. Large-bodied and flightless species suffered higher rates of extinction, with flightless species 33 times more likely to go extinct. These traits also made the birds easier and more profitable to hunt, and their lower rates of population growth made it harder to bounce back from overhunting or habitat loss.

Species native to archipelagos or single islands also had progressively higher extinction probabilities, about 24 times more likely than their widespread counterparts, likely due to the loss of behavioral responses to predators. In the absence of predators, birds became naive, making them tame and easy to hunt once humans arrived.

The scientists excluded New Zealand from their primary analysis of Pacific islands, due to the fact that the archipelago is well-studied and less subject to the same uncertainties as other islands.

New Zealand is the most well-documented case of how human colonization and the ensuing overhunting can devastate island bird life. The country has lost over 30 percent of its native land birds, the most notable of which is the moa, which was able to grow over over three meters tall. But that extinction rate is still relatively low by Pacific island standards. New Zealand’s large size, rugged topography, and plentiful rains set it apart from other islands in the region and have allowed species that would have otherwise gone extinct, such as the flightless kiwi and kakapo, to survive.

Extinctions of seabirds and songbirds also occurred during human colonization of the Pacific islands. The study suggests that more than 10 percent of total global bird biodiversity was lost during this extinction event, making it the largest extinction event to occur in the last 11,700 years.

Promoted Comments

Confirmation might not be glamorous, but it's is one of the keys that makes science such a powerful tool!.

Right, because if we didn't study things merely because they would be unsurprising if true, then we'd end up believing a lot of things that would be unsurprising if true, but that weren't actually true!

Or, at least, not be able to say anything better than "Well, it wouldn't be surprising if true." Which is even less glamorous than saying "Well, it wasn't a surprise, but now we know it's true."

97 Reader Comments

Maybe the fact that large flightless birds where almost exclusively living over sever islands or isolated land masses by then, when we know they once thrived in america and eurasia; points towards a larger pattern of extinction for these birds, much older than human migrations.

Maybe it was not evil humanity doing evil, but something that happened because mammals had long before out-competed them on most other ecological niches, and it was a matter of time before a cat or a rat arrived there over some tree trunk? Except it was an ape, so its somehow bad.

This can't be right, only modern western civilization pillages alien environments into extinction, while the natives coexist with nature in blissful harmony. Or have I interpreted the subtext of James Cameron's "Avatar" completely wrong?

YES! ... AND you misinterpreted the article wrong. These people were colonizing the area and were not "natives"! Therefore, they had no special knowledge nor interest in cultivating the resources responsibly as it must of felt like a free-for-all when they arrived and they could lazily kill all the easy food without regard for the "native" animals and their ability to keep pace.

In regards to the movie, your interpretation that the movie only applied to "modern western civilization" is your inability to grasp symbolism. Just because the movie was set in that regard doesn't preclude it's message from being much broader than your narrow interpretation but then some people see art in paintings and some just see paint on a canvas.

Since you didn't understand the movie, it isn't modernization that makes societies irresponsible and selfish, it's people who look for shortcuts to prosperity without any regard for the consequences it has on anyone or anything else. It's an entitlement state of mind that is the disease of humans as no other creature has a limitless feeling of need for more than it requires. Thus, the refusal of humans to control this mentality that has been exemplified tragically throughout history rather than embracing it with Wall Street type "capitalism" makes our species a significant threat to all we encounter including ourselves.

Humans are the cancer of the planet, whatever place we are living, the ecosystem is destroyed to meet our living standard or for food.

Without humans the planet, in fact the entire universe has no purpose. If we don't exist to observe the universe it ceases to exist. But, feel free to off yourself if you think it's the right thing to do, you know to slow down the "cancer".

I don't know why you've been downvoted, this is pretty true. Our interest in conserving species and the environment is only valuable in that it entails preserving our own environment. The "universe has no purpose" might be a little overstated, both because we may not be the only intelligent life and because it's questionable that the presence of intelligent life gives it purpose, but so far as we know, no one but us cares one way or the other about the survival of other species on this planet.

The environment and its inhabitants make a complicated system and it does us well to try to understand it before we go about changing it--unforeseen consequences and all that. Perceiving humans as a disease upon the earth is dramatic but makes no sense; we are one of earth's species and have as much a right to be here as any other and are unique among them in that we can learn and respond quickly and (sometimes) intelligently. Other lifeforms have less influence on their environment, that's true, but they also give no shits should they inadvertently eat another species out of existence.

Humans are the cancer of the planet, whatever place we are living, the ecosystem is destroyed to meet our living standard or for food.

Without humans the planet, in fact the entire universe has no purpose. If we don't exist to observe the universe it ceases to exist. But, feel free to off yourself if you think it's the right thing to do, you know to slow down the "cancer".

I don't know why you've been downvoted, this is pretty true. Our interest in conserving species and the environment is only valuable in that it entails preserving our own environment. The "universe has no purpose" might be a little overstated, both because we may not be the only intelligent life and because it's questionable that the presence of intelligent life gives it purpose, but so far as we know, no one but us cares one way or the other about the survival of other species on this planet.

The environment and its inhabitants make a complicated system and it does us well to try to understand it before we go about changing it--unforeseen consequences and all that. Perceiving humans as a disease upon the earth is dramatic but makes no sense; we are one of earth's species and have as much a right to be here as any other and are unique among them in that we can learn and respond quickly and (sometimes) intelligently. Other lifeforms have less influence on their environment, that's true, but they also give no shits should they inadvertently eat another species out of existence.

Most of what you said is true, except for not understanding why the downvoting. The problem is, what you said is true, but what he/she said is NOT true.

"Without humans the planet, in fact the entire universe has no purpose.": True, but tautological, since even WITH humans the planet, in fact the entire universe has no "purpose."

"If we don't exist to observe the universe it ceases to exist.": False. This is probably from reading some obsolete mystical quantum mechanics interpretation. What really happens is "parts" of the universe observes other "parts," simply by interacting. Every single interaction causes observation, and "wave function collapse," if that is a thing. You and I have no special status.

"But, feel free to off yourself if you think it's the right thing to do, you know to slow down the 'cancer'": Nasty, ad-hominem attack on someone making a valid point: we are damaging our OWN FUTURE, and we don't seem able to control ourselves, JUST LIKE A CANCER.

So hunting animals that we eat to extinction is making them more useful????? Tell that to the sad hunters who could never find another one after they killed them all and had to move on to not-so-easy prey.

Most of the animals we eat are domesticated and cannot be "eaten to extinction"

Just because the movie was set in that regard doesn't preclude it's message from being much broader than your narrow interpretation but then some people see art in paintings and some just see paint on a canvas.

Since you didn't understand the movie, it isn't modernization that makes societies irresponsible and selfish, it's people who look for shortcuts to prosperity without any regard for the consequences it has on anyone or anything else. It's an entitlement state of mind that is the disease of humans as no other creature has a limitless feeling of need for more than it requires. Thus, the refusal of humans to control this mentality that has been exemplified tragically throughout history rather than embracing it with Wall Street type "capitalism" makes our species a significant threat to all we encounter including ourselves.

Wow -- how arrogant. Question: Does everyone who sees the art in paintings actually see/infer the same symbolism? Or is it just your understanding of some work of art that controls? Why don't you do a quick search for symbolism in Avatar. See what you come up with. Sure; there are some common themes. But there is a variety of symbols people "see" in this movie. And that's the nature of art. It's up for interpretation.

And while there are obvious examples of the excesses of human greed, the flip side is what advances would be made in the world if not based upon a risk/reward system? Do you honestly believe you'd be sitting here in front of your computer today were we all to just rely upon altruistic acts of geniuses or otherwise highly creative people? You're dreaming if you think we'd be in the same technological place.

And since you're using and benefiting from some of the same "lack of control" excesses of others, are you not complicit in their deeds?

Why worry? According to Darwinists hundreds of new species appear every day!

Really? Assuming Darwinists are a pejorative term for evolutionary biologists, you can point to a credible source for this claim?

I mean no disrespect, but a 2010 UN Environment Programme report estimates that 150-200 species of plant, insect, bird and mammal become extinct every 24 hours.

Also, speciation is supposed to be an ongoing process, if we were to believe in speciation by random mutation. There are constant discoveries of species, but it is epistemologically impossible to determine whether they are predominantly discoveries of old species or discoveries of new species.

A good Darwinist should also believe in survival of the fittest. Weaklings are to give place to stronger species.

The conclusion is obviously wrong because humans can't possibly have any affect on their environment. It was probably due to an asteroid, or volcanoes,... glaciers? um gamma ray burst or... I KNOW ... ALIENS.

Humans are no different from any other species on the planet. We are part of nature no matter how much the ignorant want to believe otherwise. We compete with other species for the same land and natural resources. the better equipped is the one that usually wins. This has been an on going struggle waged since the beginning on this planet among ALL species. Life on this planet is hard. Modern city dwelling humans have forgotten this thanks to all our modern conveniences.

The conclusion is obviously wrong because humans can't possibly have any affect on their environment. It was probably due to an asteroid, or volcanoes,... glaciers? um gamma ray burst or... I KNOW ... ALIENS.

It doesn't surprise me at all. A modern rice farmer is claimed to sustain a person on about 1/10th of the areal that the first farmers used. And they used burning for fertilization, meaning swapping the areal every other year.

Not coincidentally then, the news circulating a few years ago was that a geographer providing default forest area projections to be used for climate research found that the continental wide forests were trashed some 8 000 years ago, about the time the new practice swept the globe. (But I believe since then, the case of the Amazon rain forest is outstanding. It was probably only partially deforested, some 10 % on satellite photos according to some, before it grew up again after abandonment.)

Using the famous estimate that 99.9 % of species has gone extinct, we would have had ~ 5 billion species since eukaryotes appeared ~ 2.5 billion years ago after the oxygenation of the atmosphere.

That would make a "speciation rate" of the biosphere of ~ 2 species/year under a linear estimate. That is disregarding that the diversity was first increasing rapidly and now is slowly so according to estimates as I know them. The later makes the estimate roughly valid, within an order of magnitude or so, in modern times.

Perceiving humans as a disease upon the earth is dramatic but makes no sense; we are one of earth's species and have as much a right to be here as any other and are unique among them in that we can learn and respond quickly and (sometimes) intelligently. Other lifeforms have less influence on their environment, that's true, but they also give no shits should they inadvertently eat another species out of existence.

Most of what you said is true, except for not understanding why the downvoting. The problem is, what you said is true, but what he/she said is NOT true.

"But, feel free to off yourself if you think it's the right thing to do, you know to slow down the 'cancer'": Nasty, ad-hominem attack on someone making a valid point: we are damaging our OWN FUTURE, and we don't seem able to control ourselves, JUST LIKE A CANCER.

Not to get into the argument and how it was made, but this is an unfactual "truth". As this article demonstrates we are much less affecting the environment than we used to be despite our increasing population (soon to be peaking before going down again).

Some of that comes from precisely us being able to control ourselves, and nature, better than before. Say, using less antibiotics under medical care. (Happened here in Sweden anyway.)

Whether we are "damaging" it is a term in need of a testable definition. Do we mean reversible loss of bioproductivity (say), or less reversible loss of geocaches (takes geological times to resupply)? What time horizon are we speaking of, decades (so economical loss), or centuries (so generational loss of opportunities), or even longer perspectives (so no loss or damage at all)?

This can't be right, only modern western civilization pillages alien environments into extinction, while the natives coexist with nature in blissful harmony. Or have I interpreted the subtext of James Cameron's "Avatar" completely wrong?

The natives in Dances with Smurfs were not primitives. They were the possessors and operators of a sophisticated biotechnology that included direct neural control of useful species plus global memory storage and retrieval.

Of course, if Cameron does make a sequel he will probably ignore this, thereby wrecking it, just as the sequels of The Matrix ignored important implications of the first movie.

Maybe the fact that large flightless birds where almost exclusively living over sever islands or isolated land masses by then, when we know they once thrived in america and eurasia; points towards a larger pattern of extinction for these birds, much older than human migrations.

Maybe it was not evil humanity doing evil, but something that happened because mammals had long before out-competed them on most other ecological niches, and it was a matter of time before a cat or a rat arrived there over some tree trunk? Except it was an ape, so its somehow bad.

Actually, I suspect a large part of the damage was caused by the rats and pigs that came along with the humans. Even an eight foot bird might have real trouble defending its nests against a sounder of swine.

Overhunting by humans, exacerbated by forest clearance, was a major cause of prehistoric bird extinctions.

Is this actually true? I didn't think Pacific Islanders were big into forest clearance.

Let's google: "forest loss in new zealand".

1st hit: "Past and future trajectories of forest loss in New Zealand".

First sentence of abstract: "Historically, New Zealand was dominated by forest below the alpine treeline, but about 1000 years of Polynesian and European colonisation has resulted in the destruction of nearly three-quarters of the indigenous forest cover."

First sentence of abstract: "Despite small and transient populations, early Māori transformed large areas of New Zealand's forest landscapes."

Last sentence of abstract: "Rapid forest loss at the time of human settlement is recurrent across eastern Polynesia, so understanding this dynamic in New Zealand has implications for the region as a whole."

Evolution in action. If those birds didn't want to be eaten, they shouldn't have lost their adaptations that made them competitive against Humans. Or they could have evolved to taste terrible instead of apparently delicious, that might have bought them a couple of centuries.

Humans are the cancer of the planet, whatever place we are living, the ecosystem is destroyed to meet our living standard or for food.

While I understand where you are coming from, if you placed a lion on that same island, given enough time, it would do the same thing. Is every predator a cancer?

The difference between humans and other predators is that other predators won't know when to stop while humans could either find a way to leave the island to find more food or realize that their only food source was about to run out and become more conservative or even domesticate the birds.

They weren't native Americans at the time, they were aliens (in the other sense of the word) and so the alien invaders wiped out the native megafauna (or so some say).

So the conclusion we can draw from all of this is that a non-native comes to a new area and decimates a large percentage of the local ecosystem. Then, once the ecosystem adapts, they become native and live happily in balance until the next new-big-thing comes and starts the process all over again.

I'm going to sidestep all this arguing about the environment and just point out that I really like the sketch at the top of this article. Those moa are awesome--you can really see the dinosaur ancestry in the neck and legs.

While I understand where you are coming from, if you placed a lion on that same island, given enough time, it would do the same thing. Is every predator a cancer?

Obviously, using "cancer" to describe humanity's effect on the planet is an emotional appeal. No sense it trying to parse its logic.

As far as your lion comment, if a pride of lions were introduced into island full of unsuspecting prey, I think lions and the flightless birds will gradually come to a balance, and they'll gradually evolve to counterbalance each others characteristics and the amount of resources on the island (food for the bird, flora, water, terrain, etc).

I think it's highly unlikely for a lion, or whatever animal that fills the role of an apex predator, to hunt the prey it relies on for survival to extinction. For the most part, megafauna that rely on a single food source would be really dependent on the survival of that food source. If the food source disappears, so do they.

Omnivorous animals, or animals that can eat many things, like rats on the other hand can likely kill off these big bird species, make them extinct, by eating the eggs. They don't rely on the eggs as they can eat other things too, so there's no regulating pressure to keep their numbers down. They'll keep eating the eggs - and reproducing, increasing their population - until the eggs are gone, and then move on to the next food source.

Quote:

The difference between humans and other predators is that other predators won't know when to stop while humans could either find a way to leave the island to find more food or realize that their only food source was about to run out and become more conservative or even domesticate the birds.

Humans don't really know when to stop. Is there any evidence that we know when to stop? We know how to keep surviving and reproducing. We're the ultimate generalists and basically can eat anything. I think that spells the end of "wild" species on the planet eventually, including those in the oceans. Everything will be farmed, be it on land or in water. Maybe there'd be these huge oases of parks and reserves where animals are left free from humans, but that's more akin to a zoo.

The alternative is human population control. That'll ultimately happen naturally as there's only so much resources on the planet. Maybe 20 billion? After that, we'd have to be able to colonize the moon and Mars and other places to keep going. On Earth, this assumes constant conditions. Climate change will render the cold latitudes livable, but the equator? Doesn't sound too good 50 years from now. The Earth is an island, and it may not be able to support 10 to 20 billion people in the future. Could be something a lot less.

Evolution in action. If those birds didn't want to be eaten, they shouldn't have lost their adaptations that made them competitive against Humans. Or they could have evolved to taste terrible instead of apparently delicious, that might have bought them a couple of centuries.

People also forget just as we have out competed many other species there are many species which still exist to day because we exist. Even some of those who are currently endangered.

It's not destroyed. It's converted into something useful. Our ability to perform this conversion effectively (very effectively, at that) is why humans are so awesome.

Exactly. Our ability to use tools, our aggressive nature, and our intelligence are a killer combination. Yes there are other animals out there that farm and cultivate other animals and living space for their own use but few are as effective at it as we are. not many people know we aren't the only ones who do what we do. There's a species of ant that raises some bug for food. But not to eat them. They use them the same way we use dairy cows. They "milk" them. there are other that farm mold. The more we learn about the other life that shares this planet with us the more we learn how alike we actually are.

It's not destroyed. It's converted into something useful. Our ability to perform this conversion effectively (very effectively, at that) is why humans are so awesome.

Exactly. Our ability to use tools, our aggressive nature, and our intelligence are a killer combination. Yes there are other animals out there that farm and cultivate other animals and living space for their own use but few are as effective at it as we are. not many people know we aren't the only ones who do what we do. There's a species of ant that raises some bug for food. But not to eat them. They use them the same way we use dairy cows. They "milk" them. there are other that farm mold. The more we learn about the other life that shares this planet with us the more we learn how alike we actually are.

The only real "exclusive" trait in humanity is language. No other animal comes close to having such a device, so their social interactions can't become complex culture over time, because they never get to invent and use symbols (even if many animals can understand basic symbol-based information on studies).

It's not destroyed. It's converted into something useful. Our ability to perform this conversion effectively (very effectively, at that) is why humans are so awesome.

Exactly. Our ability to use tools, our aggressive nature, and our intelligence are a killer combination. Yes there are other animals out there that farm and cultivate other animals and living space for their own use but few are as effective at it as we are. not many people know we aren't the only ones who do what we do. There's a species of ant that raises some bug for food. But not to eat them. They use them the same way we use dairy cows. They "milk" them. there are other that farm mold. The more we learn about the other life that shares this planet with us the more we learn how alike we actually are.

The only real "exclusive" trait in humanity is language. No other animal comes close to having such a device, so their social interactions can't become complex culture over time, because they never get to invent and use symbols (even if many animals can understand basic symbol-based information on studies).

Language and writing are what we have to thank for our current success as a species. they made it possible to collect and store knowledge and wisdom for future generation to build upon and benefit from. w/o these two things we'd still be roaming nomadic tribes of hunter/gatherers.

different societies, different cultures, different means of hunting, and different motives. earlier "indigenous" people hunted primarily for sustenance vs Europeans who were largely interested in trading/selling birds or simply hunting for sport. I'd be shocked if the inter-Island trading among indigenous people was profitable enough to encourage "overproduction."

I'd like to know the specific mechanics of how small populations of hunter-gatherers, and later small-scale farmers, could cause the extinction of hundreds of bird species. the only way I can internalize this theory is to assume only a very small population of birds on these islands and that their species differentiation was along the lines of what Darwin observed in the Galapagos. these two things could make the birds highly vulnerable to any outside pressure--making them so fragile that it it's almost difficult to not kill them.

Confirmation might not be glamorous, but it's is one of the keys that makes science such a powerful tool!.

Right, because if we didn't study things merely because they would be unsurprising if true, then we'd end up believing a lot of things that would be unsurprising if true, but that weren't actually true!

Or, at least, not be able to say anything better than "Well, it wouldn't be surprising if true." Which is even less glamorous than saying "Well, it wasn't a surprise, but now we know it's true."

Allie Wilkinson / Allie is a freelance contributor to Ars Technica. She received a B.A. in Environmental Studies from Eckerd College and a Certificate in Conservation Biology from Columbia University's Earth Institute Center for Environmental Sustainability.